Exam 22: The Origin of Species

Scientists found that different beak shapes correlate with different mating songs in Darwin's finches.Which hypothesis does this support?

NASA Scientists send a small population of dogs to a new planet in order to test if it will be hospitable for human colonization.Through a random lottery, only Great Dane and St.Bernard dog breeds are sent, and the resulting population consists of tall, longhaired dogs.After 100 years these dogs return to Earth and are no longer able to mate with Earth dogs.This scenario is an example of

Which isolating mechanism is postzygotic?

If species are competing for the same resource, one species is likely to go extinct through competitive exclusion, or natural selection will drive the evolution of

Studies of snapping shrimp on either side of the Isthmus of Panama have shown that each Caribbean shrimp species is more closely related to a Pacific shrimp species than it is to any other Caribbean shrimp species.The most likely explanation for this result is

Hybridization regularly occurs between three species of Darwin's finches on Daphne Major, but the finches are still considered different species because

The sunflower species Helianthus anomalus is thought to have been formed by hybridization between the sunflower species H.petiolaris and H.annuus because it contains a set of chromsomes from both parental species.H.anomalus is most likely an example of instantaneous speciation through

If populations within the same area split into species, the process is known as

When species are kept separate by preventing the formation of hybrid zygotes, the mechanism that keeps the species separate is known as a _____________ isolating mechanism.

In 1938, scientists found a population of coelacanths in the Indian Ocean.This fish species is considered a "living fossil" and appears not to have changed morphologically for 80 million years.This discovery supports the ___________ model of evolution.

The hundreds of species of Drosophila in Hawaii exhibit different mating rituals.This isolating mechanism is

Lake Victoria is famous for its variety of cichlid fishes.In fact, they offer the most diverse assembly of vertebrates presently known to science.One trait that scientists have focused on as one possible reason for their adaptability is

Imagine two species of birds with similar beak sizes and diets.Where the two species are allopatric, we would expect that their beak sizes

In the southeastern U.S., two species of wild lettuce (Lactuca) do not usually form hybrids, because they bloom at different seasons.The means of isolation appears to be

A type of isolating mechanism that leads to reproductive isolation after a hybrid zygote has formed is called a _____________ isolating mechanism.

Which statement is true about speciation on island archipelagos?

The type of speciation that results in the formation of separate species as a result of geographic isolation is called ____________ speciation.

Once species have formed, they keep their identity by

The model that assumes that evolution proceeds with slow successive change in a given evolutionary line is referred to as

Which is an example of temporal isolation?